Organic light emitting display device

ABSTRACT

Disclosed is an organic light emitting display device which may improve reliability. The organic light emitting display device includes light emitting elements arranged in an active area, crack prevention layers arranged in a non-active area along the perimeter of the active area, and at least one crack detection line arranged between the active area and the crack prevention layers, and judges whether or not a crack is generated through an output resistance value from the at least one crack detection line and may thus raise yield.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. Application No. 16/190,852,filed on Nov. 14, 2018, which claims the benefit of Korean PatentApplication No. 10-2017-0157583, filed on Nov. 23, 2017, which is herebyincorporated by reference as if fully set forth herein.

BACKGROUND Technical Field

The present disclosure relates to an organic light emitting displaydevice, and more particularly, to an organic light emitting displaydevice which may improve reliability.

DESCRIPTION OF THE RELATED ART

Image display devices, which display various pieces of information on ascreen, are a core technology in the age of information andcommunication and have been developed to satisfy thinness, light-weight,portability and high-performance trends. Therefore, as a flat paneldisplay device which can reduce weight and volume to make up fordrawbacks of a cathode ray tube (CRT), an organic light emitting displaydevice (OLED), which controls the amount of light emitted from anorganic light emitting layer and thus displays an image, is now in thespotlight. Such an organic light emitting display device is aself-luminous display and has advantages, such as low power consumption,high response speed, high luminous efficacy, high brightness and wideviewing angle.

Such an organic light emitting display device is formed mainly using anorganic thin film having flexibility and elasticity and may thus beimplemented as a flexible display device. However, in the case of aflexible organic light emitting display device, cracks are easilygenerated by external force during movement or handling of the flexibleorganic light emitting display device. If external moisture or oxygenpenetrates into the organic light emitting display device through suchcracks, elements in the organic light emitting display device are easilyoxidized and, thus, reliability of the organic light emitting displaydevice may be lowered.

BRIEF SUMMARY

Accordingly, the present disclosure is directed to an organic lightemitting display device that substantially obviates one or more problemsdue to limitations and disadvantages of the related art.

In various embodiments, the present disclosure provides an organic lightemitting display device which may improve reliability.

Additional advantages, objects, and features of the disclosure will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of thedisclosure. The objectives and other advantages of the disclosure may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the disclosure, as embodied and broadly described herein, anorganic light emitting display device is provided that includes lightemitting elements positioned in an active area of the display device, acrack prevention layer positioned in a non-active area of the displaydevice, the non-active area positioned adjacent to a perimeter of theactive area, and at least one crack detection line positioned betweenthe active area and the crack prevention layer. The at least one crackdetection element may be utilized to determine whether or not a crack isgenerated through measuring an output resistance value of the at leastone crack detection line and may thus raise yield.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure areexemplary and explanatory and are intended to provide furtherexplanation of the disclosure as claimed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the disclosure andtogether with the description serve to explain the principle of thedisclosure. In the drawings:

FIG. 1 is a plan view illustrating an organic light emitting displaydevice in accordance with one embodiment of the present disclosure;

FIG. 2 is a circuit diagram illustrating a sub-pixel shown in FIG. 1 ;

FIG. 3 is a cross-sectional view of the organic light emitting displaydevice, taken along line I-I′ of FIG. 1 ;

FIGS. 4A to 4C are plan views illustrating crack prevention layers andcrack prevention holes shown in FIG. 3 ;

FIG. 4D is a plan view illustrating crack detection lines shown in FIG.3 ;

FIG. 5 is a cross-sectional view illustrating an organic light emittingdisplay device in accordance with another embodiment of the presentdisclosure;

FIG. 6 is a plan view illustrating resistance measurement units tomeasure output resistances of crack detection lines shown in FIG. 5 ;

FIG. 7 is a cross-sectional view illustrating an organic light emittingdisplay device in accordance with another embodiment of the presentdisclosure;

FIG. 8 is a cross-sectional view illustrating another embodiment ofcrack detection lines shown in FIG. 7 ;

FIG. 9 is a plan view illustrating resistance measurement units tomeasure output resistances of the crack detection lines shown in FIG. 7;

FIG. 10 is a cross-sectional view illustrating an organic light emittingdisplay device in accordance with another embodiment of the presentdisclosure;

FIG. 11 is a cross-sectional view illustrating another embodiment ofcrack detection lines shown in FIG. 10 ;

FIG. 12 is a plan view illustrating an organic light emitting displaydevice in accordance with yet another embodiment of the presentdisclosure;

FIG. 13 is a plan view illustrating another embodiment of a bending areashown in FIG. 12 ;

FIG. 14 is a cross-sectional view of the organic light emitting displaydevice, taken along line II-II′ of FIG. 13 ; and

FIG. 15 is a cross-sectional view of the organic light emitting displaydevice, taken along line III-III′ of FIG. 13 .

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings.

FIG. 1 is a plan view illustrating an organic light emitting displaydevice in accordance with one embodiment of the present disclosure.

The organic light emitting display device shown in FIG. 1 includes anorganic light emitting display panel 100, and a driving unit 150 todrive the organic light emitting display panel 100.

The driving unit 150 includes a circuit film 152 and a drivingintegrated circuit 154 mounted on the circuit film 152.

The driving integrated circuit 154 generates a driving signal, etc. todrive the organic light emitting display panel 100 and supplies thedriving signal to the organic light emitting display panel 100 throughthe circuit film 152.

One end of the circuit film 152 is connected to pad parts of the organiclight emitting display panel 100, and the other end of the circuit film152 is connected to a printed circuit board, on which a timingcontroller, a power supply, etc. are mounted. Therefore, power voltagegenerated by the power supply is supplied to a power line 160 of theorganic light emitting display panel 100 through power supply terminals162 disposed on the circuit film 152. Here, power voltage includes atleast one of reference voltage, high voltage or low voltage. AlthoughFIG. 1 illustrates only one power line 160, two or more power lines 160may be formed so as to supply a plurality of different driving voltages.Such a power line 160 is arranged inside a dam 106 in a non-active areaNA, and a crack detection line170 and crack prevention layers 182, whichare parallel to the power line 160, are arranged outside the dam 106 inthe non-active area NA. The crack detection line 170 may take the formof a circuit element, a conductive member, a circuit member, aconductive interconnection line, a line through which a current runs asa circuit element, a connection to a resistor, a capacitor plate, aninductor winding, a circuit connection to a capacitor, or any conductiveline. The term crack detection line is therefore used herein in thebroadest sense include a member, element or any of the examples providedherein. If a particular meaning that is only a subset of the broaddefinition stated above for a selected embodiment, it will beparticularly stated and explained for that embodiment.

The organic light emitting display panel 100 is divided into an activearea AA provided on a substrate 101, and the non-active area NA arrangedaround the active area AA. If the substrate 101 is a glass or plasticsubstrate, the substrate 101 may be formed of a polyimide-based orpolycarbonate-based material and thus have flexibility.

The active area AA displays an image through unit pixels arranged in amatrix. The unit pixel includes red (R), green (G) and blue (B)sub-pixels SP or includes red (R), green (G), blue (B) and white (W)sub-pixels SP. Each of the sub-pixels SP includes a pixel drivingcircuit and a light emitting element 120 connected to the pixel drivingcircuit, as exemplarily shown in FIG. 2 .

The pixel driving circuit includes first and second switchingtransistors ST1 and ST2, a driving transistor DT and a storage capacitorCst. Here, the pixel driving circuit is not limited to the configurationof FIG. 2 and pixel driving circuits having various configurations maybe used.

The storage capacitor Cst is connected between a scan terminal of thedriving transistor DT and a low voltage (EVSS) supply line, chargesdifferential voltage therebetween and supplies it as driving voltage ofthe driving transistor DT.

The first switching transistor ST1 is turned-on under control of a firstscan line SL1 and transmits data voltage from a data line DL to a gateelectrode of the driving transistor DT.

The second switching transistor ST2 is turned-on under control of asecond scan line SL2 and transmits reference voltage from a referenceline RL to a source electrode of the driving transistor DT. Further, thesecond switching transistor ST2 may transmit current of the drivingtransistor DT to the reference line RL in a sensing mode. The first andsecond switching transistors ST1 and ST2 may be controlled by thedifferent scan lines SL1 and SL2 or controlled by the same scan line.

The driving transistor DT is switched by a data signal supplied from thefirst switching transistor ST1 and thus controls current transmittedfrom a high voltage (EVDD) supply line to the organic light emittingelement 120.

Such a driving transistor DT, 130 includes, as exemplarily shown in FIG.3 , a semiconductor layer 134 arranged on a buffer layer 112, a gateelectrode 132 overlapping the semiconductor layer 134 with a gateinsulating film 102 interposed therebetween, and source and drainelectrodes 136 and 138 formed on an interlayer film 114 and contactingthe semiconductor layer 134. Here, the semiconductor layer 134 may beformed of at least one of an amorphous semiconductor material, apolycrystalline semiconductor material or an oxide semiconductormaterial.

The organic light emitting element 120 is electrically connected betweena source terminal of the driving transistor DT and the low voltage(EVSS) supply line and emits light by current corresponding to a datasignal supplied from the driving transistor DT. For this purpose, theorganic light emitting element 120 includes an anode 122 and a cathode126 disposed opposite to each other with an organic layer 124therebetween. The anode 122 is connected to the source electrode 138 ofthe driving transistor DT exposed through a pixel contact hole formedthrough a protective film 116 and a planarization layer 118, and isexposed by a bank 128 arranged to provide a light emitting area. Theorganic layer 124 is formed on the anode 122 and the bank 128. Theorganic layer 124 may include a hole injection layer/a hole transportlayer/a light emitting layer/an electron transport layer/an electroninjection layer, etc. The cathode 126 is formed on the organic layer 124so as to be disposed opposite to the anode 122 with the organic layer124 therebetween.

Therefore, each of the red (R), green (G), blue (B) and white (W)sub-pixels SP controls the magnitude of current flowing from a highvoltage power supply (EVDD) to the organic light emitting element 120using switching of the driving transistor DT according to the datasignal, and thus emits light through the light emitting layer of theorganic light emitting element 120, thereby expressing a designatedcolor.

An encapsulation structure 140 (which may be referred to herein asencapsulation unit 140) having a multilayer structure is arranged on theorganic light emitting element 120. The encapsulation unit 140 preventsexternal moisture or oxygen from penetrating into the organic lightemitting element 120, which is vulnerable to external moisture oroxygen. For this purpose, the encapsulation unit 140 includes aplurality of inorganic encapsulation layers 142 and 146 and an organicencapsulation layer 144 arranged between the inorganic encapsulationlayers 142 and 146, and the inorganic encapsulation layer 146 isarranged as the uppermost layer. Here, the encapsulation layer 140includes at least two inorganic encapsulation layers 142 and 146 and atleast one organic encapsulation layer 144. In the present disclosure, astructure of the encapsulation unit 140 in which the organicencapsulation layer 144 is arranged between first and second inorganicencapsulation layers 142 and 146 will be exemplarily described. In thepresent disclosure, the organic encapsulation layer 144 at leastpartially covers a side surface of the dam 106, the inorganicencapsulation layer 142 totally covers the dam 106, and the inorganicencapsulation layer 146 at least partially covers the dam 106, inparticular, the inorganic encapsulation layer 146 covers a top surfaceof the dam 106.

The first inorganic encapsulation layer 142 is formed on the cathode 126so as to be closest to the organic light emitting element 120. The firstinorganic encapsulation layer 142 is formed of an inorganic insulatingmaterial which may be deposited at a low temperature, such as siliconnitride (SiN_(x)), silicon oxide (SiO_(x)), silicon oxynitride (SiON) oraluminum oxide (Al₂O₃). The first inorganic encapsulation layer 142 isdeposited in a low temperature atmosphere and may thus prevent damage toa light emitting stack 124, which cannot withstand high temperatures,during the deposition process of the first inorganic encapsulation layer142.

The organic encapsulation layer 144 serves as a buffer to reduce stressbetween respective layers due to bending of the organic light emittingdisplay panel 100 and reinforces planarization performance. The organicencapsulation layer 144 is formed of an organic insulating material,such as acrylic resin, epoxy resin, polyimide, polyethylene or siliconoxycarbide (SiOC). Such an organic encapsulation layer 144 may be formedso as to diffuse to the dam 106, or to diffuse to a region in front ofthe non-active area NA, in which signal pads are arranged, past the dam106.

The second inorganic encapsulation layer 146 is formed so as to coverthe upper and side surfaces of the organic encapsulation layer 144 andthe first inorganic encapsulation layer 142. That is, the secondinorganic encapsulation layer 146 may be formed not only in the activearea AA but also in a remaining region of the non-active area NA exceptfor a region of the non-active area in which the signal pads arearranged. Thereby, the second inorganic encapsulation layer 146minimizes and prevents penetration of external moisture or oxygen intothe first inorganic encapsulation layer 142 and the organicencapsulation layer 144. The second inorganic encapsulation 146 isformed of an inorganic insulating material, such as silicon nitride(SiN_(x)), silicon oxide (SiO_(x)), silicon oxynitride (SiON) oraluminum oxide (Al₂O₃).

In the non-active area NA, the power line 160, the dam 106, the crackdetection line 170 and the crack prevention layers 182 are arranged.

The power line 160 supplies power voltage including at least one ofreference voltage Vref, high voltage EVDD or low voltage EVSS. The powerline 160 is arranged to surround the remainder of the active area AAexcept for one side of the active area AA, to which the circuit film 152is attached. A gate driving unit (not shown) may be arranged between thepower line 160 and the active area AA. The gate driving unit mainly usesa gate-in-panel (GIP) type which is embedded in the non-active area NA(a bezel area) of the display panel 100, and is formed through the sameprocess as thin film transistors arranged in the active area.

If the organic encapsulation layer 144 is formed through an inkjetmethod, the dam 106 is arranged so as to prevent the organicencapsulation layer 144 of a liquid type from diffusing into thenon-active area NA. Such a dam 106 may prevent the organic encapsulationlayer 144 from diffusing to the signal pads arranged in the outermostregion of the non-active area NA. For this purpose, as shown in FIG. 1 ,the dam 106 may be formed to completely surround the active area AA, inwhich the organic light emitting elements 120 are arranged, and thusformed between the active area AA and the non-active area NA.

A plurality of crack prevention layers 182 is formed along the perimeterof the active area AA so as to prevent a crack generated at the edge ofthe inorganic light emitting display panel 100 from propagating to theactive area AA. The crack prevention layers 182 may prevent the organiclight emitting elements 120, the transistors ST1, ST2 and DT, thecapacitors Cst, signal lines SL, DL and RL and power lines PL, which arearranged in the active area AA, from being damaged. In the presentdisclosure, the crack prevention layers 182 may be formed partially ortotally along the perimeter of the active area AA.

For this purpose, the crack prevention layers 182 are spaced apart fromeach other by crack prevention holes 180. Here, the crack preventionlayers 182 are formed of the same material as at least one of aplurality of inorganic insulating films. For example, the crackprevention layers 182 may include a first crack prevention layer 182 aformed of the same material as the gate insulating film 102, on thebuffer layer 112, and a second crack prevention layer 182 b formed ofthe same material as the interlayer film 114, on the first crackprevention layer 182 a. In the present disclosure, the crack preventionhole 180 may be disposed between the crack prevention layer 182 and thecrack detection line 170.

The crack prevention layers 182 may be arranged in a straight line, asexemplarily shown in FIG. 4A, or be arranged in a zigzag line, asexemplarily shown in FIG. 4B, or the crack prevention layers 182 havinga polygonal structure, a circular structure or a combined structurethereof may be arranged in a matrix, as exemplarily shown in FIG. 4C.Here, the respective crack prevention layers 182 may have the sameshape, or at least one of heights, lengths, widths or shapes of therespective crack prevention layers 182 may be different.

A propagation path of a crack generated at the edge of the display panel100 is elongated by the crack prevention layers 182 and, thus, it isdifficult to propagate cracks to the active area AA. Therefore, thecrack prevention layers 182 may prevent cracks generated at the edge ofthe display panel 100 from damaging the elements 120, ST1, ST2, DT andCst and the signal lines SL, DL and RL of the active area AA.

The crack detection line 170 judges whether or not there is a crackhaving a high strength, which is generated at the edge of the displaypanel 100 and is thus not blocked by the crack prevention holes 180 andthe crack prevention layers 182 and propagates. For this purpose, atleast one crack detection line 170 is positioned between at least one ofthe crack prevention layers 182 and the crack prevention holes 180, andthe dam 106. The crack detection line 170 is formed so as to surround atleast three sides of the active area AA. For example, the crackdetection line 170 is formed in a U-shape or an open frame shape, a partof which is open. Respective sides of the crack detection line 170 maybe formed in a straight line or a zigzag line, as exemplarily shown inFIG. 1 , along the crack prevention layers 182 shown in FIGS. 4A or 4B,or be formed in a shape in which plural diamonds having a vacant centralarea are connected in a line (e.g., a plurality of diamond shapesconnected to one another with each of the diamond shapes having a vacantcentral area), as exemplarily shown in FIG. 4D. The crack detection line170 is formed of the same material as at least one of the gate electrode132, the source electrode 136 or the drain electrode 138 of the drivingtransistor DT, on the same layer as the at least one of the gateelectrode 132, the source electrode 136 or the drain electrode 138 ofthe driving transistor DT.

Crack detection terminals 164 connected to both ends of the crackdetection line 170 are positioned on the circuit film 152, the printedcircuit board or the non-active area NA, as exemplarily shown in FIG. 1. A resistance measurement circuit (or unit) contacts the crackdetection terminals 164 and thus measures an output resistance valuefrom the crack detection line 170. If the output resistance value isdetected as an infinite value, it is judged that a crack is generated atthe crack detection line 170 and thus propagates to the active area AA.Further, if the output resistance value is detected as a proper valuewhich is smaller than the infinite value, it is judged that no crack isgenerated at the crack detection line 170.

As such, in the present disclosure, the crack detection line 170 ispositioned between the crack prevention layers 182 and the active areaAA. Whether or not a crack propagates to the active area AA may bejudged by measuring the output resistance value from the crack detectionline 170 during inspection of each unit process or during finalinspection. Thereby, in the present disclosure, a dark spot generated bypenetration of moisture or oxygen into a crack may be prevented and,thus, reliability may be improved. Further, in the present disclosure,whether or not a crack is generated may be judged through inspectionprior to product shipping and, thus, yield may be increased.

FIG. 5 is a cross-sectional view illustrating an organic light emittingdisplay device in accordance with another embodiment of the presentdisclosure.

The organic light emitting display device shown in FIG. 5 includes thesame elements as the organic light emitting display device shown in FIG.3 except that a plurality of dams 106 is arranged and a plurality ofcrack detection lines 170 is arranged in a horizontal direction on thesame plane. Therefore, a detail description of the elements of theorganic light emitting display device in accordance with thisembodiment, which are the same as those of the organic light emittingdisplay device in accordance with the earlier embodiment, will beomitted.

The dams 106 shown in FIG. 5 are arranged in parallel between anon-active area NA and an active area AA. For example, the dams 106include a first dam 106 a adjacent to the active area AA and a seconddam 106 b adjacent to the non-active area NA. Both the first and seconddam 106 a, 106 b may be positioned in the non-active area NA, with thefirst dam 106 a being positioned between the active area AA and thesecond dam 106 b. The first and second dams 106 a and 106 b prevent anorganic encapsulation layer 144 of a liquid type from diffusing tosignals pads of the non-active area NA, when the organic encapsulationlayer 144 of the liquid type is dropped onto the active area AA. Thecrack detection lines 170 are positioned between crack prevention layers182 and the active area AA and detect the horizontal position of acrack. For example, the crack detection lines 170 include first andsecond crack detection lines 172 and 174 which are arranged in parallelin the horizontal direction on the same plane, i.e., a gate insulatingfilm 102, as exemplarily shown in FIG. 6 . Here, the crack detectionlines 170 are not limited to the structure and the number shown in FIGS.5 and 6 , and two or more crack detection lines 170 may be arranged onthe substrate, either adjacent to each other or in different locations.

The first crack detection line 172 is positioned adjacent to the activearea AA, and the second crack detection line 174 is positioned betweenthe first crack detection line 172 and crack prevention layers 182. Thefirst and second crack detection lines 172 and 174 are formed of thesame material as one of a gate electrode 132 and a source electrode 136,on the same layer as the one of the gate electrode 132 and the sourceelectrode 136. For example, the first and second crack detection lines172 and 174 are formed of the same material as the source electrode 136,on an interlayer film 114. Output resistance values from the first andsecond crack detection lines 172 and 174 are measured by resistancemeasurement circuits 178 (which may be referred to herein as resistancemeasurement units 178). The resistance measurement circuits 178 mayinclude any circuitry operable to measure resistances of the first andsecond crack detection lines 172 and 174, including, for example,circuitry which applies a known current and determines the resistance bymeasuring the resulting voltage, and/or circuitry which applies a knownvoltage and determines the resistance by measuring the resultingcurrent. Other circuitry may be suitable for use as the resistancemeasurement circuits 178, including any circuitry operable to detectelectrical continuity of the first and second crack detection lines 172and 174 (e.g., when the crack detection lines 172 and 174 are unbroken)and to detect an open circuit condition (e.g., an infinite or very highresistance), such as when there is a crack through at least one of thefirst and second crack detection lines 172 and 174.

If both the output resistance values from the first and second crackdetection lines 172 and 174 are measured as infinite values, it isjudged that a crack propagates to the active area AA and thus acorresponding display panel 100 is defective. Further, if both theoutput resistance values from the first and second crack detection lines172 and 174 are measured as proper values, it is judged that no crackpropagates to the active area AA and thus the corresponding displaypanel 100 is normal. Further, if the output resistance value from thefirst crack detection line 172 is measured as a proper value which islower than an infinite value and the output resistance value from thesecond crack detection line 174 is measured as an infinite value, it isjudged that a crack propagates to a region between the first and secondcrack detection lines 172 and 174 but does not propagate to the activearea AA and thus the corresponding display panel 100 is normal.

As such, in the organic light emitting display device in accordance withthis embodiment of the present disclosure, a plurality of crackdetection lines 170 is arranged in parallel in the horizontal directionbetween the crack prevention layers 182 and the active area AA. Not onlywhether or not a crack propagates to the active area AA but also thehorizontal position of the crack may be judged by measuring the outputresistance values from the crack detection lines 170 during inspectionof each unit process or during final inspection. Thereby, in the presentdisclosure, a dark spot generated by penetration of moisture or oxygeninto a crack may be prevented and, thus, reliability may be improved.Further, in the present disclosure, whether or not a crack is generatedmay be judged through inspection prior to product shipping and, thus,yield may be increased.

FIG. 7 is a cross-sectional view illustrating an organic light emittingdisplay device in accordance with another embodiment of the presentdisclosure.

The organic light emitting display device shown in FIG. 7 includes thesame elements as the organic light emitting display device shown in FIG.3 except that a plurality of crack detection lines 170 is arranged invertical and horizontal directions. Therefore, a detail description ofthe elements of the organic light emitting display device in accordancewith this embodiment, which are the same as those of the organic lightemitting display device in accordance with the earlier embodiment, willbe omitted.

The crack detection lines 170 shown in FIG. 7 are positioned betweencrack prevention layers 182 and an active area AA and detect thehorizontal and vertical positions of a crack. For example, the crackdetection lines 170 include first and second crack detection lines 172and 174. Here, the crack detection lines 170 are not limited to thestructure and the number shown in FIG. 7 , and two or more crackdetection lines 170 may be arranged on the substrate, either adjacent toeach other or in different locations.

The first crack detection lines 172 are positioned adjacent to theactive area AA. The first crack detection lines 172 include a firstlower crack detection line 172 a and a first upper crack detection line172 b which are arranged on different planes. The first lower crackdetection line 172 a may overlap the first upper crack detection line172 b with at least one insulating film therebetween, as exemplarilyshown in FIG. 7 , or the first lower crack detection line 172 a and thefirst upper crack detection line 172 b may be alternately arranged, asexemplarily shown in FIG. 8 . For example, the first lower crackdetection line 172 a is formed of the same material as a gate electrode132, on a gate insulating film 102, and the first upper crack detectionline 172 b is formed of the same material as source and drain electrodes136 and 138, on an interlayer film 114. In this case, the first lowercrack detection line 172 a and the first upper crack detection line 172b overlap each other or are alternately arranged with the interlayerfilm 114 therebetween. The term “overlap” is used herein to indicatethat any two or more elements are arranged in an overlapping manner, anddoes not otherwise indicate a specific positional relationship betweenthe two or more elements. For example, the first lower crack detectionline 172 a may overlap the first upper crack detection line 172 b eventhough the first upper crack detection line 172 b may be oriented abovethe first lower crack detection line 172 a, as shown in FIG. 7 .

The second crack detection lines 174 are positioned between the firstcrack detection lines 172 and the crack prevention layers 182. Thesecond crack detection lines 174 include a second lower crack detectionline 174 a and a second upper crack detection line 174 b which arearranged on different planes. The second lower crack detection line 174a may overlap the second upper crack detection line 174 b with at leastone insulating film therebetween. For example, the second lower crackdetection line 174 a is formed of the same material as the gateelectrode 132, on the gate insulating film 102, and the second uppercrack detection line 174 b is formed of the same material as the sourceand drain electrodes 136 and 138, on the interlayer film 114. In thiscase, the second lower crack detection line 174 a and the second uppercrack detection line 174 b overlap each other or are alternatelyarranged with the interlayer film 114 therebetween.

Output resistance values from the first and second lower crack detectionlines 172 a and 174 a and the first and second upper crack detectionlines 172 b and 174 b are respectively measured by resistancemeasurement units 178, as exemplarily shown in FIG. 9 .

If both the output resistance values from the first and second lowercrack detection lines 172 a and 174 a and the first and second uppercrack detection lines 172 b and 174 b are measured as infinite values,it is judged that a crack propagates to the active area AA and thus acorresponding display panel 100 is defective.

If both the output resistance values from the first and second lowercrack detection lines 172 a and 174 a and the first and second uppercrack detection lines 172 b and 174 b are measured as proper values, itis judged that no crack propagates to the active area AA and thus thecorresponding display panel 100 is normal.

If the output resistance values from the first and second lower crackdetection lines 172 a and 174 a are measured as proper values and theoutput resistance values from the first and second upper crack detectionlines 172 b and 174 b are measured as infinite values, it is judged thata crack does not propagate up to the first and second lower crackdetection lines 172 a and 174 a.

If the output resistance values from the first lower and upper crackdetection lines 172 a and 172 b are measured as proper values and theoutput resistance values from the second lower and upper crack detectionlines 174 a and 174 b are measured as infinite values, it is judged thata crack does not propagate up to the first lower and upper crackdetection lines 172 a and 172 b.

As such, in the organic light emitting display device in accordance withthis embodiment of the present disclosure, a plurality of crackdetection lines 170 is arranged in parallel in the horizontal andvertical directions between the crack prevention layers 182 and theactive area AA. The horizontal and vertical positions of a crack may bejudged by measuring the output resistance values from the crackdetection lines 170 during inspection of each unit process or duringfinal inspection and, thus, whether or not the crack propagates to theactive area AA may be judged. Thereby, in the present disclosure, a darkspot generated by penetration of moisture or oxygen into a crack may beprevented and, thus, reliability may be improved. Further, in thepresent disclosure, whether or not a crack is generated may be judgedthrough inspection prior to product shipping and, thus, yield may beincreased.

FIG. 10 is a cross-sectional view illustrating an organic light emittingdisplay device in accordance with another embodiment of the presentdisclosure.

The organic light emitting display device shown in FIG. 10 includes thesame elements as the organic light emitting display device shown in FIG.3 except that an auxiliary crack detection line 176 to judge whether ornot a crack propagates to the inside of an active area AA is furtherprovided. Therefore, a detail description of the elements of the organiclight emitting display device in accordance with this embodiment, whichare the same as those of the organic light emitting display device inaccordance with the earlier embodiment, will be omitted.

The auxiliary crack detection line 176 is positioned inside a dam 106.That is, the auxiliary crack detection line 176 is arranged in parallelto a power line 160, between the dam 106 and the power line 160. Whetheror not a crack propagates to an area inside the dam 106 is judged bymeasuring an output resistance value from the auxiliary crack detectionline 176. Therefore, the organic light emitting display device shown inFIG. 10 may not only judge whether or not a crack propagates to theactive area AA from the non-active area NA through crack detection lines170 but also judge whether or not the crack propagates to the inside ofthe active area AA through the auxiliary crack detection line 176.

That is, if the output resistance value from the auxiliary crackdetection line 176 is measured as an infinite value, it is judged that acrack propagates to the area inside the dam 106, i.e., the inside of theactive area AA, and thus a corresponding display panel 100 is defective.If the output resistance value from the auxiliary crack detection line176 is measured as a proper value which is lower than the infinitevalue, it is judged that a crack does not propagate to the area insidethe dam 106, i.e., the inside of the active area AA, and thus thecorresponding display panel 100 is normal.

Besides, an auxiliary crack detection line 176 may be arranged so as tooverlap a crack prevention layer 182, as exemplarily shown in FIG. 11 .Thereby, dimensions of a non-active area NA, i.e., a bezel area,occupied by the auxiliary crack detection line 176 may be reduced and,thus, the bezel area may be minimized.

FIG. 12 is a plan view illustrating an organic light emitting displaydevice in accordance with yet another embodiment of the presentdisclosure.

The organic light emitting display device shown in FIG. 12 includes thesame elements as the organic light emitting display device shown in FIG.3 except that a bending area BA is provided within a non-active area NAso that the organic light emitting display device is bendable.Therefore, a detail description of the elements of the organic lightemitting display device in accordance with this embodiment, which arethe same as those of the organic light emitting display device inaccordance with the earlier embodiment, will be omitted.

The bending area BA shown in FIG. 12 is an area, which is bent towardsthe rear surface of the active area AA based on a bending line BL, andcorresponds to an area arranged between an upper region of the activearea AA and a circuit film 152. Therefore, out of the entire screen ofthe organic light emitting display device, dimensions occupied by theactive area AA are maximized and dimensions occupied by a bezel areacorresponding to the non-active area NA are minimized.

Crack prevention holes 180 and crack prevention layers 182 arepositioned between the bending area BA and the active area AA and maythus prevent a crack from propagating to the active area AA due tostress generated during bending of the bending area BA.

Although FIG. 12 exemplarily illustrates a structure in which thebending area BA is arranged at one side of the active area AA, bendingareas BA may be arranged at up to four sides of the active area AA, asexemplarily shown in FIG. 13 . The bending area BA in which a gatedriving unit 184 and a circuit film 152 are arranged is bent towards therear surface of the active area AA based on the bending line BL, asexemplarily shown in FIG. 14 .

In this case, at least one of crack prevention holes 180, crackprevention layers 182 or crack detection lines 170 is positioned betweenthe active area AA and the bending area BA. Particularly, at least oneof the crack prevention holes 180, the crack prevention layers 182 orthe crack detection lines 170 is arranged between the gate driving unit184 positioned in the bending area BA and the active area AA, asexemplarily shown in FIG. 14 . Second crack prevention holes 190 toexpose a substrate 101 are positioned between the power supply line 160and the crack detection line 170 positioned in the bending area BA, asexemplarily shown in FIG. 15 . The second crack prevention holes 190 areformed by removing at least one inorganic insulating film selected fromthe group consisting of a buffer layer 112, a gate insulating film 102,an interlayer film 114 and first and second inorganic encapsulationlayers 142 and 146, which are formed of inorganic insulating materials,between the crack detection line 170 and the power supply line 160.Thereby, propagation of a crack, generated during bending of the bendingarea BA, to the active area AA through the inorganic insulating filmsmay be prevented.

The crack prevention holes 180 and the crack prevention layers 182 arepositioned between the bending area BA and the crack detection line 170and prevent a crack from propagating to the active area AA due to stressgenerated during bending of the bending area BA. The crack detectionline 170 is positioned between the crack prevention layers 182 and theactive area AA and judges whether or not a crack propagates to theactive area AA due to stress generated during bending of the bendingarea BA.

As such, in the organic light emitting display device in accordance withthis embodiment of the present disclosure, the crack detection lines 170are arranged between the bending area BA and the active area AA. Thehorizontal and vertical positions of a crack may be judged by measuringthe output resistance values from the crack detection lines 170 duringinspection of each unit process or during final inspection and, thus,whether or not the crack propagates to the active area AA may be judged.Thereby, in the present disclosure, a dark spot generated by penetrationof moisture or oxygen into a crack may be prevented and, thus,reliability may be improved. Further, in the present disclosure, whetheror not a crack is generated may be judged through inspection prior toproduct shipping and, thus, yield may be increased.

Although the organic light emitting display panel 100 including thesubstrate 101 in accordance with the present disclosure is exemplarilydescribed, the present disclosure is applicable to an organic lightemitting display panel without a substrate so as to implement a slim andflexible structure. In this case, an organic light emitting displaypanel without a substrate is manufactured by forming a plurality oflight emitting elements 120 on a substrate 101 and then removing thesubstrate 101.

As apparent from the above description, in an organic light emittingdisplay device in accordance with the present disclosure, at least onecrack detection line is positioned between crack prevention layers andan active area. Whether or not a crack propagates to the active area maybe judged by measuring an output resistance value from the crackdetection line during inspection of each unit process or during finalinspection. Thereby, in the present disclosure, a dark spot generated bypenetration of moisture or oxygen into a crack may be prevented and,thus, reliability may be improved. Further, in the present disclosure,whether or not a crack is generated may be judged through inspectionprior to product shipping and, thus, yield may be increased.

The present disclosure also relates to and is not limited to thefollowing aspects.

In the present disclosure, the power line and the crack detection lineare disposed in parallel with each other.

In the present disclosure, the power line partially overlaps the dam andthe crack prevention layer, and the crack detection line partiallyoverlaps the crack prevention layer.

In the present disclosure, the organic encapsulation layer at leastpartially covers a side surface of the dam.

In the present disclosure, the plurality of inorganic encapsulationlayers comprises a first inorganic encapsulation layer and a secondinorganic encapsulation layer, wherein the first inorganic encapsulationlayer totally covers the dam, and the second inorganic encapsulationlayer at least partially covers the dam.

In the present disclosure, the second inorganic encapsulation layercovers a top surface of the dam.

In the present disclosure, at least one crack prevention holes isdisposed between the crack prevention layer and the crack detectionline.

In the present disclosure, a bending area is disposed in the non-activearea, and at least one of the crack prevention layer and the at leastone crack detection line is positioned between the bending area and theactive area.

In the present disclosure, the power line and the crack detection lineare parallel with each other in a bending area.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present disclosurewithout departing from the spirit or scope of the disclosure. Thus, itis intended that the present disclosure cover the modifications andvariations of this disclosure provided they come within the scope of theappended claims and their equivalents.

The various embodiments described above can be combined to providefurther embodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

What is claimed is:
 1. An organic light emitting display device,comprising: light emitting elements positioned in an active area of thedisplay device; at least one crack prevention hole positioned in anon-active area of the display device, the non-active area positionedadjacent to a perimeter of the active area, and the at least one crackprevention hole exposing a buffer layer; at least one dam surroundingthe active area and positioned inwardly from the at least one crackprevention hole; at least one crack detection line positioned adjacentto the at least one dam; and at least one protective film covering theat least one crack prevention hole.
 2. The organic light emittingdisplay device according to claim 1, wherein the at least one crackprevention hole penetrates an interlayer film and a gate insulating filmto expose the buffer layer.
 3. The organic light emitting display deviceaccording to claim 1, further comprising: at least one crack preventionlayer adjacent to the at least one crack prevention hole.
 4. The organiclight emitting display device according to claim 3, wherein the at leastone crack prevention layer comprises two or more crack preventionlayers.
 5. The organic light emitting display device according to claim3, wherein the at least one crack prevention layer comprises aninterlayer film and a gate insulating film.
 6. The organic lightemitting display device according to claim 1, further comprising: thinfilm transistors electrically connected to the light emitting elements,wherein the at least one crack detection line includes a same materialas one of gate electrodes and source electrodes of the thin filmtransistors.
 7. The organic light emitting display device according toclaim 6, wherein at least one crack detection line is positioned on asame layer as the one of gate electrodes and the source electrodes ofthe thin film transistors.
 8. The organic light emitting display deviceaccording to claim 1, wherein the at least one crack detection linecomprises a plurality of crack detection lines positioned on differentplanes to overlap each other or to be alternately disposed.
 9. Theorganic light emitting display device according to claim 8, furthercomprising: thin film transistors electrically connected to the lightemitting elements, wherein the at least one crack detection linescomprise: a lower crack detection line comprising a same material asgate electrodes of the thin film transistors, and positioned on a samelayer as the gate electrodes of the thin film transistors; and an uppercrack detection line comprising a same material as source electrodes ofthe thin film transistors, and positioned on a same layer as the sourceelectrodes of the thin film transistors.
 10. The organic light emittingdisplay device according to claim 9, further comprising: an interlayerfilm positioned between the lower crack detection line and the uppercrack detection line.
 11. The organic light emitting display deviceaccording to claim 1, further comprising: a power line positionedbetween the dam and the active area; and an auxiliary crack detectionline positioned between the power line and the dam.
 12. The organiclight emitting display device according to claim 11, wherein the powerline and the crack detection line are disposed in parallel with eachother.
 13. The organic light emitting display device according to claim11, wherein the power line partially overlaps the dam and the crackprevention layer, and the crack detection line partially overlaps thecrack prevention layer.
 14. The organic light emitting display deviceaccording to claim 1, further comprising: an auxiliary crack detectionline positioned under the crack prevention layer to overlap the crackprevention layer.
 15. The organic light emitting display deviceaccording to claim 1, wherein: an output resistance value of the atleast one crack detection line is an infinite value when the at leastone crack detection line has at least one crack therein; and the outputresistance value of the at least one crack detection line is less thanthe infinite value when the at least one crack detection line does nothave any cracks therein.
 16. An organic light emitting display device,comprising: light emitting elements positioned in an active area of thedisplay device; a crack prevention layer positioned in a non-active areaof the display device, the non-active area positioned adjacent to aperimeter of the active area; at least one dam surrounding the activearea; at least one crack detection line positioned between the dam andthe crack prevention layer; and a power line positioned inwardly oroutwardly from the at least one dam and overlapping with at least aportion of the at least one dam.
 17. The organic light emitting displaydevice according to claim 16, wherein: an output resistance value of theat least one crack detection line is an infinite value when the at leastone crack detection line has at least one crack therein; and the outputresistance value of the at least one crack detection line is less thanthe infinite value when the at least one crack detection line does nothave any cracks therein.
 18. The organic light emitting display deviceaccording to claim 16, further comprising: thin film transistorselectrically connected to the light emitting elements, wherein the atleast one crack detection line comprises a same material as one of gateelectrodes and source electrodes of the thin film transistors.
 19. Theorganic light emitting display device according to claim 16, furthercomprising: an encapsulation structure including at least one inorganicencapsulation layers and an organic encapsulation layer.
 20. The organiclight emitting display device according to claim 16, wherein the atleast one crack detection line is covered by a protective film.